This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The long term goals of this project are to study neural plasticity of the adult mammalian visual system by adding new sensory input. Experiments that enhance rather than ablate sensory input offer a new avenue of research for answering fundamental questions about the plasticity of the adult visual system and have important implications for the rational design of gene therapy retinal prostheses. We have chosen red-green color vision as a model system in which gain of function can be monitored quantitatively at the level of the retina using the electroretinogram and at the level of the visual cortex with behavioral tests of color vision. Experiments for this project are designed to determine whether adding a third cone type via viral mediated delivery of a photopigment gene to the retina in a dichromatic adult squirrel monkey can expand his/her sensory capacity and change color vision behavior from dichromatic to trichromatic. Currently, animals that received subretinal injections and were tested using the electroretinogram at the Medical College of Wisconsin before moving to Washington in April of 2009 are undergoing daily behavioral tests of color vision. In addition, untreated control animals are also undergoing daily behavioral tests of color vision.